1. Technical Field
The present invention relates to a droplet-ejecting head, a method for manufacturing the droplet-ejecting head, and a droplet-ejecting apparatus.
2. Related Art
Ink jet processes are high-definition, high-speed printing processes and therefore are now in practical use. The following technique is useful in ejecting ink droplets: a technique using a piezoelectric actuator including electrodes and a piezoelectric layer sandwiched therebetween. A typical material for forming the piezoelectric layer is lead zirconate titanate (Pb(Zr, Ti)O3 or PZT), which is a perovskite oxide, as disclosed in, for example, JP-A-2001-223404. Piezoelectric actuators for use in droplet-ejecting apparatuses represented by ink jet printers need to have improved displacement characteristics and dielectric characteristics.
It has been pointed out that in a piezoelectric actuator having such a structure, a material contained in a lower electrode diffuses into PZT to negatively affect a piezoelectric element. For example, JP-A-2007-300071 discloses a technique for controlling the composition of an electrode for the purpose of preventing the interdiffusion between materials contained in electrodes and a piezoelectric layer.